Блочные и монокристаллические пленки сплава висмут--сурьма 3-12 ат% с подслоем сурьмы

We investigated the effect of the antimony underlayer (10 nm) on the structure and galvanomagnetic properties of bismuth-antimony solid solution thin films (3-12 at.% Sb). The films were obtained on mica substrates by discrete vacuum evaporation and zone recrystallization. We found that the misorientation of the crystallite plane (111) increases relative to the film plane as well as the crystallite sizes decrease. The antimony underlayer does not change the crystallographic orientation during recrystallization and increases the film adhesion. The change in the galvanomagnetic coefficients when using a sublayer is due to the classical dimensional effect and increasing plane deformation.

Tensoresistive properties of single crystals TlIn1−xGaxSe2

In this work, single crystals of TlIn[Formula: see text]Ga[Formula: see text]Se2 solid solutions were grown by the methods of zone recrystallization, technologies for the manufacture of strain gauges based on them were developed and the tensoresistive properties of these phases were studied, the coefficient of strain sensitivity was determined by the static method depending on the temperature, the magnitude of mechanical deformation and optical illumination. Revealing that the single crystals have a high strain sensitivity coefficient, by the variation of the composition, quantity of mechanical deformation and the optical illumination, it is possible to control the phase coefficients investigated tensosensitivity.

Варизонные гетероструктуры Al-=SUB=-x-=/SUB=-In-=SUB=-y-=/SUB=-Ga-=SUB=-1-x-y-=/SUB=-P-=SUB=-z-=/SUB=-As-=SUB=-1-z-=/SUB=-/GaAs для фотоэлектрических преобразователей

The AlxInyGa1-x-yPzAs1-z/GaAs graded-gap heterostructures were grown by the temperature gradient zone recrystallization with a liquid zone reciprocating, where energy band gap varied from 1.43 to 2.2 eV. The influence of technological parameters on the varying in the energy band gap of the grown AlxInyGa1-x-yPzAs1-z/GaAs solid solutions is investigated. In the p-AlxInyGa1-x-yPzAs1-z/n-GaAs heterostructure, the maximum energy band gap gradient of 10490 eV/cm is reached, and an increase in the external quantum efficiency is shown in the wavelength range of 500-900 nm.

Zone Recrystallization of Zirconium and Hafnium

The work studied the possibility of obtaining of the high-purity samples of zirconium and hafnium by the method of zone recrystallization of round rods with electron-beam heating in a vacuum of 1∙10-4 Pa. Some meltings were carried out in a constant electric field with the variability of its connection. It is shown that the simultaneous passage of several refining processes (evaporation of highly volatile metallic impurities, zone recrystallization with directional displacement of impurities to the end of the sample, electrotransport) made it possible to efficient refining of zirconium both from metallic impurities and from interstitial impurities. The best degree of purification was achieved when zone melting carrying out in an electric field directed opposite to the zone movement. In this case, the displacement of interstitial impurity ions coincided with the direction of movement of the liquid zone. Samples of zirconium with a purity of 99.89 wt. % were obtained (the concentration of aluminum was reduced by 5, iron - 11, copper - 45, chromium - 75, silicon - 10, titanium - 2.5, oxygen - 3.3, nitrogen - 3, carbon - 2 times). The hafnium samples refined by the zone recrystallization method were characterized by a purity of 99.85 wt. %. The concentrations of both all metal impurities and interstitial impurities were significantly reduced (concentration in wt% oxygen was 0.011, carbon - 0.0018, nitrogen - 5∙10-5). A study of gas evolution from samples of iodide hafnium and refined hafnium was carried out. It was found that the maximum gas release peak fell on the temperature range of 500 ... 550 °C. The use of an integrated approach, including high-temperature heating, stages of zone melting at different rates, and thermal cycling in the range of the polymorphic transformation temperature, made it possible to obtain single-crystal hafnium samples. According to X-ray diffraction data, the parameters of the hafnium crystal lattice were determined: а = (0.31950 ± 5·10-5) nm and с = (0.50542 ± 5·10-5) nm (at 298 K), which corresponds to the density ρ = 13.263 g/cm3 and axial ratio с/a = 1.5819.

The investigation of the acousto-photovoltaic effect in single crystals TlIn1−xGaxSe2

In this work, TlIn[Formula: see text]Ga[Formula: see text]Se2 single crystals were grown by zone recrystallization methods and their X-ray phase analysis was performed. The lattice parameters were determined and it was found that crystals based on the original TlIn[Formula: see text]Ga[Formula: see text]Se2 compound crystallized in the same tetragonal symmetry, the space group [Formula: see text]. It was revealed that with partial substitution of indium atoms by gallium atoms in the TlIn[Formula: see text]Ga[Formula: see text]Se2 lattice, the parameters of unit cells change according to the additivity law. First time it was found that with the simultaneous influence of electromagnetic and sound waves, an electromotive force (e.m.f.) occurs or short circuit current. The studies were carried out in the frequency range of electromagnetic radiation of 50–143 kHz. It was revealed that when the investigated crystals were irradiated with magnetic radiation in the absence of sound waves, there was no e.m.f. on the electrodes as well as memory when exposed only to sound. Based on the existing theoretical information, the nature of the revealed single crystal of the acousto-photovoltaic effect was explained.

Effect of Antimony Buffer Layer on the Electric and Magnetic Properties of 200 and 600 nm Thick Bismuth Films on Mica Substrate

We report on the production of 200 and 600 nm thick Bi films on mica substrate with 10 nm thick Sb sublayer between Bi and mica. Two types of films have been studied: block and single crystal. Films were obtained using the thermal evaporation technique using continuous and discrete spraying. Discrete spraying allows smaller film blocks size: 2–6 μ m compared to 10–30 μ m, obtained by the continuous spraying. Single crystal films were made by the zone recrystallization method. Microscopic examination of Bi films with and without Sb sublayer did not reveal an essential distinction in crystal structure. A galvanomagnetic study shows that Sb sublayer results in the change of Bi films properties. Sb sublayer results in the increase of specific resistivity of block films and has no significant impact on single crystal films. For single-crystal films with Sb sublayer with a thickness of 200 nm the Hall coefficient has value 1.5 times higher than for the 600 nm thickness films at 77 K. The change of the Hall coefficient points to change of the contribution of carriers in the conductivity. This fact indicates a change in the energy band structure of the thin Bi film. The most significant impact of the Sb sublayer is on the magnetoresistance of single-crystal films at low temperatures. The increase of magnetoresistance points to the increase of mobility of the charge carriers. In case of detecting and sensing applications the increased carriers mobility can result in a faster device response time.

ZONE REFINING OF ZIRCONIUM IN AN ELECTRIC FIELD

The physical grounds and an experimental study of the efficiency of applying the zone recrystallization method in an electric field for zirconium refining from metal and gas-forming impurities are presented. The changes in the elemental composition, microhardness, and structure of the obtained ingots was investigated. It is shown that the application of the method can significantly reduce the content of interstitial impurities. Zirconium samples with a purity of 99.91 wt.% were obtained.

Изопериодические гетероструктуры Ga-=SUB=-x-=/SUB=-In-=SUB=-1-x-=/SUB=-Sb-=SUB=-y-=/SUB=-As-=SUB=-z-=/SUB=-P-=SUB=-1-y-z-=/SUB=-/InP для планарных p-n-фотодиодов

Isoperiodic heterostructures GaxIn1-xSbyAszP1-y-z/InP at a 1.06 to 1.6 μm wavelength interval were grown by the method of floating-zone recrystallization with temperature gradient. Absolute spectral sensitivity of ~ 0.59 A/W and a speed of ~ 10 ns were achieved. Threshold sensitivity for the fabricated photodiodes was in the range 2·10^-10 to 5·10^-11 W with a signal-to-noise ratio of 10.